Spectrometers are used for many purposes. For example, spectrometers are used in the detection of defects in industrial processes, satellite imaging, and laboratory research. However, these instruments have typically been too large and too costly for the consumer market.
Spectrometers detect radiation from a sample and process the resulting signal to obtain and present information about the sample that includes spectral, physical and chemical information about the sample. These instruments generally include some type of spectrally selective element to separate wavelengths of radiation received from the sample, and a first-stage optic, such as a lens, to focus or concentrate the radiation onto an imaging array.
The prior spectrometers can be less than ideal in at least some respects. Prior spectrometers having high resolution can be larger than ideal for use in many portable applications. Although prior spectrometers with decreased size have been proposed, the prior spectrometers having decreased size and optical path length can have less than ideal resolution, sensitivity and less accuracy than would be ideal. Detectors used in prior spectrometers can have detectable wavelength ranges that are less than ideal. Also, the cost of prior spectrometers can be greater than would be ideal. The prior spectrometers can be somewhat bulky, difficult to transport and the optics can require more alignment than would be ideal in at least some instances. Because of their size and cost, prior spectrometers can be difficult to integrate into other consumer appliances or devices in which a spectrometer may be useful.
The prior spectrometers may rely on detectors that are less than ideal. Prior spectrometers can rely on arrays such as CCD arrays, which are less than ideally suited to detect a light pattern incident on the array. The prior arrays can results in a greater number of element and electrical connections than would be ideal, and can increase one or more of the size, weight, or complexity of the spectrometer.
For many materials, the fundamental absorption peaks are in the mid-wavelength infrared (MWIR) to long-wavelength infrared (LWIR) range, for example about 3 to about 12 μm. Prior spectrometers configured to measure light in this range can be complex, large and expensive, due to the high cost of light sources, detectors and optics for this wavelength band. Although lower-cost, smaller spectrometers may work in shorter wavelength ranges, the results can be less than ideal.
The prior detectors for measuring light can be less than ideally suited for use with spectrometers. For example, prior spectrometers using infrared detectors may use detectors that are more complicated and expensive than would be ideal. Also, prior detectors may have pixels sizes and shapes that are less than ideally suited for use with spectrometers.
In light of the above, an improved spectrometer and interpretation of spectral data that overcomes at least some of the above mentioned deficiencies of the prior spectrometers would be beneficial. Ideally, such a spectrometer would be compact, integrated with appliances, sufficiently rugged and low in cost to be practical for end-user spectroscopic measurements of items, and convenient to use. Further, it would be helpful to provide an improved detector for a compact spectrometer, the detector having high sensitivity to a wide range of wavelengths.